/*******************************************************************************
 * Copyright 2011, 2012 Chris Banes.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.handmark.pulltorefresh.library;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.animation.DecelerateInterpolator;
import android.view.animation.Interpolator;
import android.widget.FrameLayout;
import android.widget.LinearLayout;

import com.handmark.pulltorefresh.library.internal.FlipLoadingLayout;
import com.handmark.pulltorefresh.library.internal.LoadingLayout;
import com.handmark.pulltorefresh.library.internal.RotateLoadingLayout;
import com.handmark.pulltorefresh.library.internal.Utils;
import com.handmark.pulltorefresh.library.internal.ViewCompat;

public abstract class PullToRefreshBase<T extends View> extends LinearLayout implements IPullToRefresh<T>
{

	// ===========================================================
	// Constants
	// ===========================================================

	static final boolean USE_HW_LAYERS = false;

	static final String LOG_TAG = "PullToRefresh";

	static final float FRICTION = 2.0f;

	public static final int SMOOTH_SCROLL_DURATION_MS = 200;
	public static final int SMOOTH_SCROLL_LONG_DURATION_MS = 325;
	static final int DEMO_SCROLL_INTERVAL = 225;

	static final String STATE_STATE = "ptr_state";
	static final String STATE_MODE = "ptr_mode";
	static final String STATE_CURRENT_MODE = "ptr_current_mode";
	static final String STATE_SCROLLING_REFRESHING_ENABLED = "ptr_disable_scrolling";
	static final String STATE_SHOW_REFRESHING_VIEW = "ptr_show_refreshing_view";
	static final String STATE_SUPER = "ptr_super";

	// ===========================================================
	// Fields
	// ===========================================================

	private int mTouchSlop;
	private float mLastMotionX, mLastMotionY;
	private float mInitialMotionX, mInitialMotionY;

	private boolean mIsBeingDragged = false;
	private State mState = State.RESET;
	private Mode mMode = Mode.getDefault();

	private Mode mCurrentMode;
	T mRefreshableView;
	private FrameLayout mRefreshableViewWrapper;

	private boolean mShowViewWhileRefreshing = true;
	private boolean mScrollingWhileRefreshingEnabled = false;
	private boolean mFilterTouchEvents = true;
	private boolean mOverScrollEnabled = true;
	private boolean mLayoutVisibilityChangesEnabled = true;

	private Interpolator mScrollAnimationInterpolator;
	private AnimationStyle mLoadingAnimationStyle = AnimationStyle.getDefault();

	private LoadingLayout mHeaderLayout;
	private LoadingLayout mFooterLayout;

	private OnRefreshListener<T> mOnRefreshListener;
	private OnRefreshListener2<T> mOnRefreshListener2;
	private OnPullEventListener<T> mOnPullEventListener;

	private SmoothScrollRunnable mCurrentSmoothScrollRunnable;

	// ===========================================================
	// Constructors
	// ===========================================================

	public PullToRefreshBase(Context context)
	{
		super(context);
		init(context, null);
	}

	public PullToRefreshBase(Context context, AttributeSet attrs)
	{
		super(context, attrs);
		init(context, attrs);
	}

	public PullToRefreshBase(Context context, Mode mode)
	{
		super(context);
		mMode = mode;
		init(context, null);
	}

	public PullToRefreshBase(Context context, Mode mode, AnimationStyle animStyle)
	{
		super(context);
		mMode = mode;
		mLoadingAnimationStyle = animStyle;
		init(context, null);
	}

	@Override
	public void addView(View child, int index, ViewGroup.LayoutParams params)
	{

		final T refreshableView = getRefreshableView();

		if (refreshableView instanceof ViewGroup)
		{
			((ViewGroup) refreshableView).addView(child, index, params);
		} else
		{
			throw new UnsupportedOperationException("Refreshable View is not a ViewGroup so can't addView");
		}
	}

	@Override
	public final boolean demo()
	{
		if (mMode.showHeaderLoadingLayout() && isReadyForPullStart())
		{
			smoothScrollToAndBack(-getHeaderSize() * 2);
			return true;
		} else if (mMode.showFooterLoadingLayout() && isReadyForPullEnd())
		{
			smoothScrollToAndBack(getFooterSize() * 2);
			return true;
		}

		return false;
	}

	@Override
	public final Mode getCurrentMode()
	{
		return mCurrentMode;
	}

	public void setCurrentMode(Mode mode)
	{
		this.mCurrentMode = mode;
	}

	@Override
	public final boolean getFilterTouchEvents()
	{
		return mFilterTouchEvents;
	}

	@Override
	public final ILoadingLayout getLoadingLayoutProxy()
	{
		return getLoadingLayoutProxy(true, true);
	}

	@Override
	public final ILoadingLayout getLoadingLayoutProxy(boolean includeStart, boolean includeEnd)
	{
		return createLoadingLayoutProxy(includeStart, includeEnd);
	}

	@Override
	public final Mode getMode()
	{
		return mMode;
	}

	@Override
	public final T getRefreshableView()
	{
		return mRefreshableView;
	}

	@Override
	public final boolean getShowViewWhileRefreshing()
	{
		return mShowViewWhileRefreshing;
	}

	@Override
	public final State getState()
	{
		return mState;
	}

	/**
	 * @deprecated See {@link #isScrollingWhileRefreshingEnabled()}.
	 */
	public final boolean isDisableScrollingWhileRefreshing()
	{
		return !isScrollingWhileRefreshingEnabled();
	}

	@Override
	public final boolean isPullToRefreshEnabled()
	{
		return mMode.permitsPullToRefresh();
	}

	@Override
	public final boolean isPullToRefreshOverScrollEnabled()
	{
		return VERSION.SDK_INT >= VERSION_CODES.GINGERBREAD && mOverScrollEnabled && OverscrollHelper.isAndroidOverScrollEnabled(mRefreshableView);
	}

	@Override
	public final boolean isRefreshing()
	{
		return mState == State.REFRESHING || mState == State.MANUAL_REFRESHING;
	}

	@Override
	public final boolean isScrollingWhileRefreshingEnabled()
	{
		return mScrollingWhileRefreshingEnabled;
	}

	@Override
	public final boolean onInterceptTouchEvent(MotionEvent event)
	{

		if (!isPullToRefreshEnabled())
		{
			return false;
		}

		final int action = event.getAction();

		if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP)
		{
			mIsBeingDragged = false;
			return false;
		}

		if (action != MotionEvent.ACTION_DOWN && mIsBeingDragged)
		{
			return true;
		}

		switch (action)
		{
		case MotionEvent.ACTION_MOVE:
		{
			// If we're refreshing, and the flag is set. Eat all MOVE events
			if (!mScrollingWhileRefreshingEnabled && isRefreshing())
			{
				return true;
			}

			if (isReadyForPull())
			{
				final float y = event.getY(), x = event.getX();
				final float diff, oppositeDiff, absDiff;

				// We need to use the correct values, based on scroll
				// direction
				switch (getPullToRefreshScrollDirection())
				{
				case HORIZONTAL:
					diff = x - mLastMotionX;
					oppositeDiff = y - mLastMotionY;
					break;
				case VERTICAL:
				default:
					diff = y - mLastMotionY;
					oppositeDiff = x - mLastMotionX;
					break;
				}
				absDiff = Math.abs(diff);

				if (absDiff > mTouchSlop && (!mFilterTouchEvents || absDiff > Math.abs(oppositeDiff)))
				{
					if (mMode.showHeaderLoadingLayout() && diff >= 1f && isReadyForPullStart())
					{
						mLastMotionY = y;
						mLastMotionX = x;
						mIsBeingDragged = true;
						if (mMode == Mode.BOTH)
						{
							mCurrentMode = Mode.PULL_FROM_START;
						}
					} else if (mMode.showFooterLoadingLayout() && diff <= -1f && isReadyForPullEnd())
					{
						mLastMotionY = y;
						mLastMotionX = x;
						mIsBeingDragged = true;
						if (mMode == Mode.BOTH)
						{
							mCurrentMode = Mode.PULL_FROM_END;
						}
					}
				}
			}
			break;
		}
		case MotionEvent.ACTION_DOWN:
		{
			if (isReadyForPull())
			{
				mLastMotionY = mInitialMotionY = event.getY();
				mLastMotionX = mInitialMotionX = event.getX();
				mIsBeingDragged = false;
			}
			break;
		}
		}

		return mIsBeingDragged;
	}

	@Override
	public final void onRefreshComplete()
	{
		if (isRefreshing())
		{
			setState(State.RESET);
		}
	}

	@Override
	public final boolean onTouchEvent(MotionEvent event)
	{

		if (!isPullToRefreshEnabled())
		{
			return false;
		}

		// If we're refreshing, and the flag is set. Eat the event
		if (!mScrollingWhileRefreshingEnabled && isRefreshing())
		{
			return true;
		}

		if (event.getAction() == MotionEvent.ACTION_DOWN && event.getEdgeFlags() != 0)
		{
			return false;
		}

		switch (event.getAction())
		{
		case MotionEvent.ACTION_MOVE:
		{
			if (mIsBeingDragged)
			{
				mLastMotionY = event.getY();
				mLastMotionX = event.getX();
				pullEvent();
				return true;
			}
			break;
		}

		case MotionEvent.ACTION_DOWN:
		{
			if (isReadyForPull())
			{
				mLastMotionY = mInitialMotionY = event.getY();
				mLastMotionX = mInitialMotionX = event.getX();
				return true;
			}
			break;
		}

		case MotionEvent.ACTION_CANCEL:
		case MotionEvent.ACTION_UP:
		{
			if (mIsBeingDragged)
			{
				mIsBeingDragged = false;

				if (mState == State.RELEASE_TO_REFRESH && (null != mOnRefreshListener || null != mOnRefreshListener2))
				{
					setState(State.REFRESHING, true);
					return true;
				}

				// If we're already refreshing, just scroll back to the top
				if (isRefreshing())
				{
					smoothScrollTo(0);
					return true;
				}

				// If we haven't returned by here, then we're not in a state
				// to pull, so just reset
				setState(State.RESET);

				return true;
			}
			break;
		}
		}

		return false;
	}

	public final void setScrollingWhileRefreshingEnabled(boolean allowScrollingWhileRefreshing)
	{
		mScrollingWhileRefreshingEnabled = allowScrollingWhileRefreshing;
	}

	/**
	 * @deprecated See {@link #setScrollingWhileRefreshingEnabled(boolean)}
	 */
	public void setDisableScrollingWhileRefreshing(boolean disableScrollingWhileRefreshing)
	{
		setScrollingWhileRefreshingEnabled(!disableScrollingWhileRefreshing);
	}

	@Override
	public final void setFilterTouchEvents(boolean filterEvents)
	{
		mFilterTouchEvents = filterEvents;
	}

	/**
	 * @deprecated You should now call this method on the result of
	 *             {@link #getLoadingLayoutProxy()}.
	 */
	public void setLastUpdatedLabel(CharSequence label)
	{
		getLoadingLayoutProxy().setLastUpdatedLabel(label);
	}

	/**
	 * @deprecated You should now call this method on the result of
	 *             {@link #getLoadingLayoutProxy()}.
	 */
	public void setLoadingDrawable(Drawable drawable)
	{
		getLoadingLayoutProxy().setLoadingDrawable(drawable);
	}

	/**
	 * @deprecated You should now call this method on the result of
	 *             {@link #getLoadingLayoutProxy(boolean, boolean)}.
	 */
	public void setLoadingDrawable(Drawable drawable, Mode mode)
	{
		getLoadingLayoutProxy(mode.showHeaderLoadingLayout(), mode.showFooterLoadingLayout()).setLoadingDrawable(drawable);
	}

	@Override
	public void setLongClickable(boolean longClickable)
	{
		getRefreshableView().setLongClickable(longClickable);
	}

	@Override
	public final void setMode(Mode mode)
	{
		if (mode != mMode)
		{
			mMode = mode;
			updateUIForMode();
		}
	}

	public void setOnPullEventListener(OnPullEventListener<T> listener)
	{
		mOnPullEventListener = listener;
	}

	@Override
	public final void setOnRefreshListener(OnRefreshListener<T> listener)
	{
		mOnRefreshListener = listener;
		mOnRefreshListener2 = null;
	}

	@Override
	public final void setOnRefreshListener(OnRefreshListener2<T> listener)
	{
		mOnRefreshListener2 = listener;
		mOnRefreshListener = null;
	}

	/**
	 * @deprecated You should now call this method on the result of
	 *             {@link #getLoadingLayoutProxy()}.
	 */
	public void setPullLabel(CharSequence pullLabel)
	{
		getLoadingLayoutProxy().setPullLabel(pullLabel);
	}

	/**
	 * @deprecated You should now call this method on the result of
	 *             {@link #getLoadingLayoutProxy(boolean, boolean)}.
	 */
	public void setPullLabel(CharSequence pullLabel, Mode mode)
	{
		getLoadingLayoutProxy(mode.showHeaderLoadingLayout(), mode.showFooterLoadingLayout()).setPullLabel(pullLabel);
	}

	/**
	 * @param enable
	 *            Whether Pull-To-Refresh should be used
	 * @deprecated This simple calls setMode with an appropriate mode based on
	 *             the passed value.
	 */
	public final void setPullToRefreshEnabled(boolean enable)
	{
		setMode(enable ? Mode.getDefault() : Mode.DISABLED);
	}

	@Override
	public final void setPullToRefreshOverScrollEnabled(boolean enabled)
	{
		mOverScrollEnabled = enabled;
	}

	@Override
	public final void setRefreshing()
	{
		setRefreshing(true);
	}

	@Override
	public final void setRefreshing(boolean doScroll)
	{
		if (!isRefreshing())
		{
			mCurrentMode = Mode.PULL_FROM_START;
			setState(State.MANUAL_REFRESHING, doScroll);
		}
	}

	/**
	 * @deprecated You should now call this method on the result of
	 *             {@link #getLoadingLayoutProxy()}.
	 */
	public void setRefreshingLabel(CharSequence refreshingLabel)
	{
		getLoadingLayoutProxy().setRefreshingLabel(refreshingLabel);
	}

	/**
	 * @deprecated You should now call this method on the result of
	 *             {@link #getLoadingLayoutProxy(boolean, boolean)}.
	 */
	public void setRefreshingLabel(CharSequence refreshingLabel, Mode mode)
	{
		getLoadingLayoutProxy(mode.showHeaderLoadingLayout(), mode.showFooterLoadingLayout()).setRefreshingLabel(refreshingLabel);
	}

	/**
	 * @deprecated You should now call this method on the result of
	 *             {@link #getLoadingLayoutProxy()}.
	 */
	public void setReleaseLabel(CharSequence releaseLabel)
	{
		setReleaseLabel(releaseLabel, Mode.BOTH);
	}

	/**
	 * @deprecated You should now call this method on the result of
	 *             {@link #getLoadingLayoutProxy(boolean, boolean)}.
	 */
	public void setReleaseLabel(CharSequence releaseLabel, Mode mode)
	{
		getLoadingLayoutProxy(mode.showHeaderLoadingLayout(), mode.showFooterLoadingLayout()).setReleaseLabel(releaseLabel);
	}

	public void setScrollAnimationInterpolator(Interpolator interpolator)
	{
		mScrollAnimationInterpolator = interpolator;
	}

	@Override
	public final void setShowViewWhileRefreshing(boolean showView)
	{
		mShowViewWhileRefreshing = showView;
	}

	/**
	 * @return Either {@link Orientation#VERTICAL} or
	 *         {@link Orientation#HORIZONTAL} depending on the scroll direction.
	 */
	public abstract Orientation getPullToRefreshScrollDirection();

	final void setState(State state, final boolean... params)
	{
		mState = state;

		switch (mState)
		{
		case RESET:
			onReset();
			break;
		case PULL_TO_REFRESH:
			onPullToRefresh();
			break;
		case RELEASE_TO_REFRESH:
			onReleaseToRefresh();
			break;
		case REFRESHING:
		case MANUAL_REFRESHING:
			onRefreshing(params[0]);
			break;
		case OVERSCROLLING:
			// NO-OP
			break;
		}

		// Call OnPullEventListener
		if (null != mOnPullEventListener)
		{
			mOnPullEventListener.onPullEvent(this, mState, mCurrentMode);
		}
	}

	/**
	 * Used internally for adding view. Need because we override addView to
	 * pass-through to the Refreshable View
	 */
	protected final void addViewInternal(View child, int index, ViewGroup.LayoutParams params)
	{
		super.addView(child, index, params);
	}

	/**
	 * Used internally for adding view. Need because we override addView to
	 * pass-through to the Refreshable View
	 */
	protected final void addViewInternal(View child, ViewGroup.LayoutParams params)
	{
		super.addView(child, -1, params);
	}

	protected LoadingLayout createLoadingLayout(Context context, Mode mode, TypedArray attrs)
	{
		LoadingLayout layout = mLoadingAnimationStyle.createLoadingLayout(context, mode, getPullToRefreshScrollDirection(), attrs);
		layout.setVisibility(View.INVISIBLE);
		return layout;
	}

	/**
	 * Used internally for {@link #getLoadingLayoutProxy(boolean, boolean)}.
	 * Allows derivative classes to include any extra LoadingLayouts.
	 */
	protected LoadingLayoutProxy createLoadingLayoutProxy(final boolean includeStart, final boolean includeEnd)
	{
		LoadingLayoutProxy proxy = new LoadingLayoutProxy();

		if (includeStart && mMode.showHeaderLoadingLayout())
		{
			proxy.addLayout(mHeaderLayout);
		}
		if (includeEnd && mMode.showFooterLoadingLayout())
		{
			proxy.addLayout(mFooterLayout);
		}

		return proxy;
	}

	/**
	 * This is implemented by derived classes to return the created View. If you
	 * need to use a custom View (such as a custom ListView), override this
	 * method and return an instance of your custom class.
	 * <p/>
	 * Be sure to set the ID of the view in this method, especially if you're
	 * using a ListActivity or ListFragment.
	 * 
	 * @param context
	 *            Context to create view with
	 * @param attrs
	 *            AttributeSet from wrapped class. Means that anything you
	 *            include in the XML layout declaration will be routed to the
	 *            created View
	 * @return New instance of the Refreshable View
	 */
	protected abstract T createRefreshableView(Context context, AttributeSet attrs);

	protected final void disableLoadingLayoutVisibilityChanges()
	{
		mLayoutVisibilityChangesEnabled = false;
	}

	protected final LoadingLayout getFooterLayout()
	{
		return mFooterLayout;
	}

	protected final int getFooterSize()
	{
		return mFooterLayout.getContentSize();
	}

	protected final LoadingLayout getHeaderLayout()
	{
		return mHeaderLayout;
	}

	protected final int getHeaderSize()
	{
		return mHeaderLayout.getContentSize();
	}

	protected int getPullToRefreshScrollDuration()
	{
		return SMOOTH_SCROLL_DURATION_MS;
	}

	protected int getPullToRefreshScrollDurationLonger()
	{
		return SMOOTH_SCROLL_LONG_DURATION_MS;
	}

	protected FrameLayout getRefreshableViewWrapper()
	{
		return mRefreshableViewWrapper;
	}

	/**
	 * Allows Derivative classes to handle the XML Attrs without creating a
	 * TypedArray themsevles
	 * 
	 * @param a
	 *            - TypedArray of PullToRefresh Attributes
	 */
	protected void handleStyledAttributes(TypedArray a)
	{
	}

	/**
	 * Implemented by derived class to return whether the View is in a state
	 * where the user can Pull to Refresh by scrolling from the end.
	 * 
	 * @return true if the View is currently in the correct state (for example,
	 *         bottom of a ListView)
	 */
	protected abstract boolean isReadyForPullEnd();

	/**
	 * Implemented by derived class to return whether the View is in a state
	 * where the user can Pull to Refresh by scrolling from the start.
	 * 
	 * @return true if the View is currently the correct state (for example, top
	 *         of a ListView)
	 */
	protected abstract boolean isReadyForPullStart();

	/**
	 * Called by {@link #onRestoreInstanceState(Parcelable)} so that derivative
	 * classes can handle their saved instance state.
	 * 
	 * @param savedInstanceState
	 *            - Bundle which contains saved instance state.
	 */
	protected void onPtrRestoreInstanceState(Bundle savedInstanceState)
	{
	}

	/**
	 * Called by {@link #onSaveInstanceState()} so that derivative classes can
	 * save their instance state.
	 * 
	 * @param saveState
	 *            - Bundle to be updated with saved state.
	 */
	protected void onPtrSaveInstanceState(Bundle saveState)
	{
	}

	/**
	 * Called when the UI has been to be updated to be in the
	 * {@link State#PULL_TO_REFRESH} state.
	 */
	protected void onPullToRefresh()
	{
		switch (mCurrentMode)
		{
		case PULL_FROM_END:
			mFooterLayout.pullToRefresh();
			break;
		case PULL_FROM_START:
			mHeaderLayout.pullToRefresh();
			break;
		default:
			// NO-OP
			break;
		}
	}

	/**
	 * Called when the UI has been to be updated to be in the
	 * {@link State#REFRESHING} or {@link State#MANUAL_REFRESHING} state.
	 * 
	 * @param doScroll
	 *            - Whether the UI should scroll for this event.
	 */
	protected void onRefreshing(final boolean doScroll)
	{
		if (mMode.showHeaderLoadingLayout())
		{
			mHeaderLayout.refreshing();
		}
		if (mMode.showFooterLoadingLayout())
		{
			mFooterLayout.refreshing();
		}

		if (doScroll)
		{
			if (mShowViewWhileRefreshing)
			{

				// Call Refresh Listener when the Scroll has finished
				OnSmoothScrollFinishedListener listener = new OnSmoothScrollFinishedListener()
				{
					@Override
					public void onSmoothScrollFinished()
					{
						callRefreshListener();
					}
				};

				switch (mCurrentMode)
				{
				case MANUAL_REFRESH_ONLY:
				case PULL_FROM_END:
					smoothScrollTo(getFooterSize(), listener);
					break;
				default:
				case PULL_FROM_START:
					smoothScrollTo(-getHeaderSize(), listener);
					break;
				}
			} else
			{
				smoothScrollTo(0);
			}
		} else
		{
			// We're not scrolling, so just call Refresh Listener now
			callRefreshListener();
		}
	}

	/**
	 * Called when the UI has been to be updated to be in the
	 * {@link State#RELEASE_TO_REFRESH} state.
	 */
	protected void onReleaseToRefresh()
	{
		switch (mCurrentMode)
		{
		case PULL_FROM_END:
			mFooterLayout.releaseToRefresh();
			break;
		case PULL_FROM_START:
			mHeaderLayout.releaseToRefresh();
			break;
		default:
			// NO-OP
			break;
		}
	}

	/**
	 * Called when the UI has been to be updated to be in the
	 * {@link State#RESET} state.
	 */
	protected void onReset()
	{
		mIsBeingDragged = false;
		mLayoutVisibilityChangesEnabled = true;

		// Always reset both layouts, just in case...
		mHeaderLayout.reset();
		mFooterLayout.reset();

		smoothScrollTo(0);
	}

	@Override
	protected final void onRestoreInstanceState(Parcelable state)
	{
		if (state instanceof Bundle)
		{
			Bundle bundle = (Bundle) state;

			setMode(Mode.mapIntToValue(bundle.getInt(STATE_MODE, 0)));
			mCurrentMode = Mode.mapIntToValue(bundle.getInt(STATE_CURRENT_MODE, 0));

			mScrollingWhileRefreshingEnabled = bundle.getBoolean(STATE_SCROLLING_REFRESHING_ENABLED, false);
			mShowViewWhileRefreshing = bundle.getBoolean(STATE_SHOW_REFRESHING_VIEW, true);

			// Let super Restore Itself
			super.onRestoreInstanceState(bundle.getParcelable(STATE_SUPER));

			State viewState = State.mapIntToValue(bundle.getInt(STATE_STATE, 0));
			if (viewState == State.REFRESHING || viewState == State.MANUAL_REFRESHING)
			{
				setState(viewState, true);
			}

			// Now let derivative classes restore their state
			onPtrRestoreInstanceState(bundle);
			return;
		}

		super.onRestoreInstanceState(state);
	}

	@Override
	protected final Parcelable onSaveInstanceState()
	{
		Bundle bundle = new Bundle();

		// Let derivative classes get a chance to save state first, that way we
		// can make sure they don't overrite any of our values
		onPtrSaveInstanceState(bundle);

		bundle.putInt(STATE_STATE, mState.getIntValue());
		bundle.putInt(STATE_MODE, mMode.getIntValue());
		bundle.putInt(STATE_CURRENT_MODE, mCurrentMode.getIntValue());
		bundle.putBoolean(STATE_SCROLLING_REFRESHING_ENABLED, mScrollingWhileRefreshingEnabled);
		bundle.putBoolean(STATE_SHOW_REFRESHING_VIEW, mShowViewWhileRefreshing);
		bundle.putParcelable(STATE_SUPER, super.onSaveInstanceState());

		return bundle;
	}

	@Override
	protected final void onSizeChanged(int w, int h, int oldw, int oldh)
	{

		super.onSizeChanged(w, h, oldw, oldh);

		// We need to update the header/footer when our size changes
		refreshLoadingViewsSize();

		// Update the Refreshable View layout
		refreshRefreshableViewSize(w, h);

		/**
		 * As we're currently in a Layout Pass, we need to schedule another one
		 * to layout any changes we've made here
		 */
		post(new Runnable()
		{
			@Override
			public void run()
			{
				requestLayout();
			}
		});
	}

	/**
	 * Re-measure the Loading Views height, and adjust internal padding as
	 * necessary
	 */
	protected final void refreshLoadingViewsSize()
	{
		final int maximumPullScroll = (int) (getMaximumPullScroll() * 1.2f);

		int pLeft = getPaddingLeft();
		int pTop = getPaddingTop();
		int pRight = getPaddingRight();
		int pBottom = getPaddingBottom();

		switch (getPullToRefreshScrollDirection())
		{
		case HORIZONTAL:
			if (mMode.showHeaderLoadingLayout())
			{
				mHeaderLayout.setWidth(maximumPullScroll);
				pLeft = -maximumPullScroll;
			} else
			{
				pLeft = 0;
			}

			if (mMode.showFooterLoadingLayout())
			{
				mFooterLayout.setWidth(maximumPullScroll);
				pRight = -maximumPullScroll;
			} else
			{
				pRight = 0;
			}
			break;

		case VERTICAL:
			if (mMode.showHeaderLoadingLayout())
			{
				mHeaderLayout.setHeight(maximumPullScroll);
				pTop = -maximumPullScroll;
			} else
			{
				pTop = 0;
			}

			if (mMode.showFooterLoadingLayout())
			{
				mFooterLayout.setHeight(maximumPullScroll);
				pBottom = -maximumPullScroll;
			} else
			{
				pBottom = 0;
			}
			break;
		}
		setPadding(pLeft, pTop, pRight, pBottom);
	}

	protected final void refreshRefreshableViewSize(int width, int height)
	{
		// We need to set the Height of the Refreshable View to the same as
		// this layout
		LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) mRefreshableViewWrapper.getLayoutParams();

		switch (getPullToRefreshScrollDirection())
		{
		case HORIZONTAL:
			if (lp.width != width)
			{
				lp.width = width;
				mRefreshableViewWrapper.requestLayout();
			}
			break;
		case VERTICAL:
			if (lp.height != height)
			{
				lp.height = height;
				mRefreshableViewWrapper.requestLayout();
			}
			break;
		}
	}

	/**
	 * Helper method which just calls scrollTo() in the correct scrolling
	 * direction.
	 * 
	 * @param value
	 *            - New Scroll value
	 */
	protected final void setHeaderScroll(int value)
	{
		// Clamp value to with pull scroll range
		final int maximumPullScroll = getMaximumPullScroll();
		value = Math.min(maximumPullScroll, Math.max(-maximumPullScroll, value));

		if (mLayoutVisibilityChangesEnabled)
		{
			if (value < 0)
			{
				mHeaderLayout.setVisibility(View.VISIBLE);
			} else if (value > 0)
			{
				mFooterLayout.setVisibility(View.VISIBLE);
			} else
			{
				mHeaderLayout.setVisibility(View.INVISIBLE);
				mFooterLayout.setVisibility(View.INVISIBLE);
			}
		}

		if (USE_HW_LAYERS)
		{
			/**
			 * Use a Hardware Layer on the Refreshable View if we've scrolled at
			 * all. We don't use them on the Header/Footer Views as they change
			 * often, which would negate any HW layer performance boost.
			 */
			ViewCompat.setLayerType(mRefreshableViewWrapper, value != 0 ? View.LAYER_TYPE_HARDWARE : View.LAYER_TYPE_NONE);
		}

		switch (getPullToRefreshScrollDirection())
		{
		case VERTICAL:
			scrollTo(0, value);
			break;
		case HORIZONTAL:
			scrollTo(value, 0);
			break;
		}
	}

	/**
	 * Smooth Scroll to position using the default duration of
	 * {@value #SMOOTH_SCROLL_DURATION_MS} ms.
	 * 
	 * @param scrollValue
	 *            - Position to scroll to
	 */
	protected final void smoothScrollTo(int scrollValue)
	{
		smoothScrollTo(scrollValue, getPullToRefreshScrollDuration());
	}

	/**
	 * Smooth Scroll to position using the default duration of
	 * {@value #SMOOTH_SCROLL_DURATION_MS} ms.
	 * 
	 * @param scrollValue
	 *            - Position to scroll to
	 * @param listener
	 *            - Listener for scroll
	 */
	protected final void smoothScrollTo(int scrollValue, OnSmoothScrollFinishedListener listener)
	{
		smoothScrollTo(scrollValue, getPullToRefreshScrollDuration(), 0, listener);
	}

	/**
	 * Smooth Scroll to position using the longer default duration of
	 * {@value #SMOOTH_SCROLL_LONG_DURATION_MS} ms.
	 * 
	 * @param scrollValue
	 *            - Position to scroll to
	 */
	protected final void smoothScrollToLonger(int scrollValue)
	{
		smoothScrollTo(scrollValue, getPullToRefreshScrollDurationLonger());
	}

	/**
	 * Updates the View State when the mode has been set. This does not do any
	 * checking that the mode is different to current state so always updates.
	 */
	protected void updateUIForMode()
	{
		// We need to use the correct LayoutParam values, based on scroll
		// direction
		final LinearLayout.LayoutParams lp = getLoadingLayoutLayoutParams();

		// Remove Header, and then add Header Loading View again if needed
		if (this == mHeaderLayout.getParent())
		{
			removeView(mHeaderLayout);
		}
		if (mMode.showHeaderLoadingLayout())
		{
			addViewInternal(mHeaderLayout, 0, lp);
		}

		// Remove Footer, and then add Footer Loading View again if needed
		if (this == mFooterLayout.getParent())
		{
			removeView(mFooterLayout);
		}
		if (mMode.showFooterLoadingLayout())
		{
			addViewInternal(mFooterLayout, lp);
		}

		// Hide Loading Views
		refreshLoadingViewsSize();

		// If we're not using Mode.BOTH, set mCurrentMode to mMode, otherwise
		// set it to pull down
		mCurrentMode = (mMode != Mode.BOTH) ? mMode : Mode.PULL_FROM_START;
	}

	private void addRefreshableView(Context context, T refreshableView)
	{
		mRefreshableViewWrapper = new FrameLayout(context);
		mRefreshableViewWrapper.addView(refreshableView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);

		addViewInternal(mRefreshableViewWrapper, new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
	}

	private void callRefreshListener()
	{
		if (null != mOnRefreshListener)
		{
			mOnRefreshListener.onRefresh(this);
		} else if (null != mOnRefreshListener2)
		{
			if (mCurrentMode == Mode.PULL_FROM_START)
			{
				mOnRefreshListener2.onPullDownToRefresh(this);
			} else if (mCurrentMode == Mode.PULL_FROM_END)
			{
				mOnRefreshListener2.onPullUpToRefresh(this);
			}
		}
	}

	@SuppressWarnings("deprecation")
	private void init(Context context, AttributeSet attrs)
	{
		switch (getPullToRefreshScrollDirection())
		{
		case HORIZONTAL:
			setOrientation(LinearLayout.HORIZONTAL);
			break;
		case VERTICAL:
		default:
			setOrientation(LinearLayout.VERTICAL);
			break;
		}

		setGravity(Gravity.CENTER);

		ViewConfiguration config = ViewConfiguration.get(context);
		mTouchSlop = config.getScaledTouchSlop();

		// Styleables from XML
		TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PullToRefresh);

		if (a.hasValue(R.styleable.PullToRefresh_ptrMode))
		{
			mMode = Mode.mapIntToValue(a.getInteger(R.styleable.PullToRefresh_ptrMode, 0));
		}

		if (a.hasValue(R.styleable.PullToRefresh_ptrAnimationStyle))
		{
			mLoadingAnimationStyle = AnimationStyle.mapIntToValue(a.getInteger(R.styleable.PullToRefresh_ptrAnimationStyle, 0));
		}

		// Refreshable View
		// By passing the attrs, we can add ListView/GridView params via XML
		mRefreshableView = createRefreshableView(context, attrs);
		addRefreshableView(context, mRefreshableView);

		// We need to create now layouts now
		mHeaderLayout = createLoadingLayout(context, Mode.PULL_FROM_START, a);
		mFooterLayout = createLoadingLayout(context, Mode.PULL_FROM_END, a);

		/**
		 * Styleables from XML
		 */
		if (a.hasValue(R.styleable.PullToRefresh_ptrRefreshableViewBackground))
		{
			Drawable background = a.getDrawable(R.styleable.PullToRefresh_ptrRefreshableViewBackground);
			if (null != background)
			{
				mRefreshableView.setBackgroundDrawable(background);
			}
		} else if (a.hasValue(R.styleable.PullToRefresh_ptrAdapterViewBackground))
		{
			Utils.warnDeprecation("ptrAdapterViewBackground", "ptrRefreshableViewBackground");
			Drawable background = a.getDrawable(R.styleable.PullToRefresh_ptrAdapterViewBackground);
			if (null != background)
			{
				mRefreshableView.setBackgroundDrawable(background);
			}
		}

		if (a.hasValue(R.styleable.PullToRefresh_ptrOverScroll))
		{
			mOverScrollEnabled = a.getBoolean(R.styleable.PullToRefresh_ptrOverScroll, true);
		}

		if (a.hasValue(R.styleable.PullToRefresh_ptrScrollingWhileRefreshingEnabled))
		{
			mScrollingWhileRefreshingEnabled = a.getBoolean(R.styleable.PullToRefresh_ptrScrollingWhileRefreshingEnabled, false);
		}

		// Let the derivative classes have a go at handling attributes, then
		// recycle them...
		handleStyledAttributes(a);
		a.recycle();

		// Finally update the UI for the modes
		updateUIForMode();
	}

	private boolean isReadyForPull()
	{
		switch (mMode)
		{
		case PULL_FROM_START:
			return isReadyForPullStart();
		case PULL_FROM_END:
			return isReadyForPullEnd();
		case BOTH:
			return isReadyForPullEnd() || isReadyForPullStart();
		default:
			return false;
		}
	}

	/**
	 * Actions a Pull Event
	 * 
	 * @return true if the Event has been handled, false if there has been no
	 *         change
	 */
	private void pullEvent()
	{
		final int newScrollValue;
		final int itemDimension;
		final float initialMotionValue, lastMotionValue;

		switch (getPullToRefreshScrollDirection())
		{
		case HORIZONTAL:
			initialMotionValue = mInitialMotionX;
			lastMotionValue = mLastMotionX;
			break;
		case VERTICAL:
		default:
			initialMotionValue = mInitialMotionY;
			lastMotionValue = mLastMotionY;
			break;
		}

		switch (mCurrentMode)
		{
		case PULL_FROM_END:
			newScrollValue = Math.round(Math.max(initialMotionValue - lastMotionValue, 0) / FRICTION);
			itemDimension = getFooterSize();
			break;
		case PULL_FROM_START:
		default:
			newScrollValue = Math.round(Math.min(initialMotionValue - lastMotionValue, 0) / FRICTION);
			itemDimension = getHeaderSize();
			break;
		}

		setHeaderScroll(newScrollValue);

		if (newScrollValue != 0 && !isRefreshing())
		{
			float scale = Math.abs(newScrollValue) / (float) itemDimension;
			switch (mCurrentMode)
			{
			case PULL_FROM_END:
				mFooterLayout.onPull(scale);
				break;
			case PULL_FROM_START:
			default:
				mHeaderLayout.onPull(scale);
				break;
			}

			if (mState != State.PULL_TO_REFRESH && itemDimension >= Math.abs(newScrollValue))
			{
				setState(State.PULL_TO_REFRESH);
			} else if (mState == State.PULL_TO_REFRESH && itemDimension < Math.abs(newScrollValue))
			{
				setState(State.RELEASE_TO_REFRESH);
			}
		}
	}

	private LinearLayout.LayoutParams getLoadingLayoutLayoutParams()
	{
		switch (getPullToRefreshScrollDirection())
		{
		case HORIZONTAL:
			return new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.MATCH_PARENT);
		case VERTICAL:
		default:
			return new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
		}
	}

	private int getMaximumPullScroll()
	{
		switch (getPullToRefreshScrollDirection())
		{
		case HORIZONTAL:
			return Math.round(getWidth() / FRICTION);
		case VERTICAL:
		default:
			return Math.round(getHeight() / FRICTION);
		}
	}

	/**
	 * Smooth Scroll to position using the specific duration
	 * 
	 * @param scrollValue
	 *            - Position to scroll to
	 * @param duration
	 *            - Duration of animation in milliseconds
	 */
	private final void smoothScrollTo(int scrollValue, long duration)
	{
		smoothScrollTo(scrollValue, duration, 0, null);
	}

	private final void smoothScrollTo(int newScrollValue, long duration, long delayMillis, OnSmoothScrollFinishedListener listener)
	{
		if (null != mCurrentSmoothScrollRunnable)
		{
			mCurrentSmoothScrollRunnable.stop();
		}

		final int oldScrollValue;
		switch (getPullToRefreshScrollDirection())
		{
		case HORIZONTAL:
			oldScrollValue = getScrollX();
			break;
		case VERTICAL:
		default:
			oldScrollValue = getScrollY();
			break;
		}

		if (oldScrollValue != newScrollValue)
		{
			if (null == mScrollAnimationInterpolator)
			{
				// Default interpolator is a Decelerate Interpolator
				mScrollAnimationInterpolator = new DecelerateInterpolator();
			}
			mCurrentSmoothScrollRunnable = new SmoothScrollRunnable(oldScrollValue, newScrollValue, duration, listener);

			if (delayMillis > 0)
			{
				postDelayed(mCurrentSmoothScrollRunnable, delayMillis);
			} else
			{
				post(mCurrentSmoothScrollRunnable);
			}
		}
	}

	private final void smoothScrollToAndBack(int y)
	{
		smoothScrollTo(y, SMOOTH_SCROLL_DURATION_MS, 0, new OnSmoothScrollFinishedListener()
		{

			@Override
			public void onSmoothScrollFinished()
			{
				smoothScrollTo(0, SMOOTH_SCROLL_DURATION_MS, DEMO_SCROLL_INTERVAL, null);
			}
		});
	}

	public static enum AnimationStyle
	{
		/**
		 * This is the default for Android-PullToRefresh. Allows you to use any
		 * drawable, which is automatically rotated and used as a Progress Bar.
		 */
		ROTATE,

		/**
		 * This is the old default, and what is commonly used on iOS. Uses an
		 * arrow image which flips depending on where the user has scrolled.
		 */
		FLIP;

		static AnimationStyle getDefault()
		{
			return ROTATE;
		}

		/**
		 * Maps an int to a specific mode. This is needed when saving state, or
		 * inflating the view from XML where the mode is given through a attr
		 * int.
		 * 
		 * @param modeInt
		 *            - int to map a Mode to
		 * @return Mode that modeInt maps to, or ROTATE by default.
		 */
		static AnimationStyle mapIntToValue(int modeInt)
		{
			switch (modeInt)
			{
			case 0x0:
			default:
				return ROTATE;
			case 0x1:
				return FLIP;
			}
		}

		LoadingLayout createLoadingLayout(Context context, Mode mode, Orientation scrollDirection, TypedArray attrs)
		{
			switch (this)
			{
			case ROTATE:
			default:
				return new RotateLoadingLayout(context, mode, scrollDirection, attrs);
			case FLIP:
				return new FlipLoadingLayout(context, mode, scrollDirection, attrs);
			}
		}
	}

	public static enum Mode
	{

		/**
		 * Disable all Pull-to-Refresh gesture and Refreshing handling
		 */
		DISABLED(0x0),

		/**
		 * Only allow the user to Pull from the start of the Refreshable View to
		 * refresh. The start is either the Top or Left, depending on the
		 * scrolling direction.
		 */
		PULL_FROM_START(0x1),

		/**
		 * Only allow the user to Pull from the end of the Refreshable View to
		 * refresh. The start is either the Bottom or Right, depending on the
		 * scrolling direction.
		 */
		PULL_FROM_END(0x2),

		/**
		 * Allow the user to both Pull from the start, from the end to refresh.
		 */
		BOTH(0x3),

		/**
		 * Disables Pull-to-Refresh gesture handling, but allows manually
		 * setting the Refresh state via
		 * {@link PullToRefreshBase#setRefreshing() setRefreshing()}.
		 */
		MANUAL_REFRESH_ONLY(0x4);

		/**
		 * @deprecated Use {@link #PULL_FROM_START} from now on.
		 */
		public static Mode PULL_DOWN_TO_REFRESH = Mode.PULL_FROM_START;

		/**
		 * @deprecated Use {@link #PULL_FROM_END} from now on.
		 */
		public static Mode PULL_UP_TO_REFRESH = Mode.PULL_FROM_END;

		/**
		 * Maps an int to a specific mode. This is needed when saving state, or
		 * inflating the view from XML where the mode is given through a attr
		 * int.
		 * 
		 * @param modeInt
		 *            - int to map a Mode to
		 * @return Mode that modeInt maps to, or PULL_FROM_START by default.
		 */
		static Mode mapIntToValue(final int modeInt)
		{
			for (Mode value : Mode.values())
			{
				if (modeInt == value.getIntValue())
				{
					return value;
				}
			}

			// If not, return default
			return getDefault();
		}

		static Mode getDefault()
		{
			return PULL_FROM_START;
		}

		private int mIntValue;

		// The modeInt values need to match those from attrs.xml
		Mode(int modeInt)
		{
			mIntValue = modeInt;
		}

		/**
		 * @return true if the mode permits Pull-to-Refresh
		 */
		boolean permitsPullToRefresh()
		{
			return !(this == DISABLED || this == MANUAL_REFRESH_ONLY);
		}

		/**
		 * @return true if this mode wants the Loading Layout Header to be shown
		 */
		public boolean showHeaderLoadingLayout()
		{
			return this == PULL_FROM_START || this == BOTH;
		}

		/**
		 * @return true if this mode wants the Loading Layout Footer to be shown
		 */
		public boolean showFooterLoadingLayout()
		{
			return this == PULL_FROM_END || this == BOTH || this == MANUAL_REFRESH_ONLY;
		}

		int getIntValue()
		{
			return mIntValue;
		}

	}

	// ===========================================================
	// Inner, Anonymous Classes, and Enumerations
	// ===========================================================

	/**
	 * Simple Listener that allows you to be notified when the user has scrolled
	 * to the end of the AdapterView. See (
	 * {@link PullToRefreshAdapterViewBase#setOnLastItemVisibleListener}.
	 * 
	 * @author Chris Banes
	 */
	public static interface OnLastItemVisibleListener
	{

		/**
		 * Called when the user has scrolled to the end of the list
		 */
		public void onLastItemVisible();

	}

	/**
	 * Listener that allows you to be notified when the user has started or
	 * finished a touch event. Useful when you want to append extra UI events
	 * (such as sounds). See (
	 * {@link PullToRefreshAdapterViewBase#setOnPullEventListener}.
	 * 
	 * @author Chris Banes
	 */
	public static interface OnPullEventListener<V extends View>
	{

		/**
		 * Called when the internal state has been changed, usually by the user
		 * pulling.
		 * 
		 * @param refreshView
		 *            - View which has had it's state change.
		 * @param state
		 *            - The new state of View.
		 * @param direction
		 *            - One of {@link Mode#PULL_FROM_START} or
		 *            {@link Mode#PULL_FROM_END} depending on which direction
		 *            the user is pulling. Only useful when <var>state</var> is
		 *            {@link State#PULL_TO_REFRESH} or
		 *            {@link State#RELEASE_TO_REFRESH}.
		 */
		public void onPullEvent(final PullToRefreshBase<V> refreshView, State state, Mode direction);

	}

	/**
	 * Simple Listener to listen for any callbacks to Refresh.
	 * 
	 * @author Chris Banes
	 */
	public static interface OnRefreshListener<V extends View>
	{

		/**
		 * onRefresh will be called for both a Pull from start, and Pull from
		 * end
		 */
		public void onRefresh(final PullToRefreshBase<V> refreshView);

	}

	/**
	 * An advanced version of the Listener to listen for callbacks to Refresh.
	 * This listener is different as it allows you to differentiate between Pull
	 * Ups, and Pull Downs.
	 * 
	 * @author Chris Banes
	 */
	public static interface OnRefreshListener2<V extends View>
	{
		// TODO These methods need renaming to START/END rather than DOWN/UP

		/**
		 * onPullDownToRefresh will be called only when the user has Pulled from
		 * the start, and released.
		 */
		public void onPullDownToRefresh(final PullToRefreshBase<V> refreshView);

		/**
		 * onPullUpToRefresh will be called only when the user has Pulled from
		 * the end, and released.
		 */
		public void onPullUpToRefresh(final PullToRefreshBase<V> refreshView);

	}

	public static enum Orientation
	{
		VERTICAL, HORIZONTAL;
	}

	public static enum State
	{

		/**
		 * When the UI is in a state which means that user is not interacting
		 * with the Pull-to-Refresh function.
		 */
		RESET(0x0),

		/**
		 * When the UI is being pulled by the user, but has not been pulled far
		 * enough so that it refreshes when released.
		 */
		PULL_TO_REFRESH(0x1),

		/**
		 * When the UI is being pulled by the user, and <strong>has</strong>
		 * been pulled far enough so that it will refresh when released.
		 */
		RELEASE_TO_REFRESH(0x2),

		/**
		 * When the UI is currently refreshing, caused by a pull gesture.
		 */
		REFRESHING(0x8),

		/**
		 * When the UI is currently refreshing, caused by a call to
		 * {@link PullToRefreshBase#setRefreshing() setRefreshing()}.
		 */
		MANUAL_REFRESHING(0x9),

		/**
		 * When the UI is currently overscrolling, caused by a fling on the
		 * Refreshable View.
		 */
		OVERSCROLLING(0x10);

		/**
		 * Maps an int to a specific state. This is needed when saving state.
		 * 
		 * @param stateInt
		 *            - int to map a State to
		 * @return State that stateInt maps to
		 */
		static State mapIntToValue(final int stateInt)
		{
			for (State value : State.values())
			{
				if (stateInt == value.getIntValue())
				{
					return value;
				}
			}

			// If not, return default
			return RESET;
		}

		private int mIntValue;

		State(int intValue)
		{
			mIntValue = intValue;
		}

		int getIntValue()
		{
			return mIntValue;
		}
	}

	final class SmoothScrollRunnable implements Runnable
	{
		private final Interpolator mInterpolator;
		private final int mScrollToY;
		private final int mScrollFromY;
		private final long mDuration;
		private OnSmoothScrollFinishedListener mListener;

		private boolean mContinueRunning = true;
		private long mStartTime = -1;
		private int mCurrentY = -1;

		public SmoothScrollRunnable(int fromY, int toY, long duration, OnSmoothScrollFinishedListener listener)
		{
			mScrollFromY = fromY;
			mScrollToY = toY;
			mInterpolator = mScrollAnimationInterpolator;
			mDuration = duration;
			mListener = listener;
		}

		@Override
		public void run()
		{

			/**
			 * Only set mStartTime if this is the first time we're starting,
			 * else actually calculate the Y delta
			 */
			if (mStartTime == -1)
			{
				mStartTime = System.currentTimeMillis();
			} else
			{

				/**
				 * We do do all calculations in long to reduce software float
				 * calculations. We use 1000 as it gives us good accuracy and
				 * small rounding errors
				 */
				long normalizedTime = (1000 * (System.currentTimeMillis() - mStartTime)) / mDuration;
				normalizedTime = Math.max(Math.min(normalizedTime, 1000), 0);

				final int deltaY = Math.round((mScrollFromY - mScrollToY) * mInterpolator.getInterpolation(normalizedTime / 1000f));
				mCurrentY = mScrollFromY - deltaY;
				setHeaderScroll(mCurrentY);
			}

			// If we're not at the target Y, keep going...
			if (mContinueRunning && mScrollToY != mCurrentY)
			{
				ViewCompat.postOnAnimation(PullToRefreshBase.this, this);
			} else
			{
				if (null != mListener)
				{
					mListener.onSmoothScrollFinished();
				}
			}
		}

		public void stop()
		{
			mContinueRunning = false;
			removeCallbacks(this);
		}
	}

	static interface OnSmoothScrollFinishedListener
	{
		void onSmoothScrollFinished();
	}

}
